Manufacture of motor fuel



June 30, 1942.

v. ATwELL MANUFACTURE 0F MOTOR FUEL Filed Nov. 30, 1939 c my. m N @n 2 A w, am

Patented June 30, 1942 UETE 2,288,262 MANUFACTURE oF iuo'ron FUEL Harold V. Atwell, Beacon, N. Y., assigner to Gasoline Products Company, Inc.,fJersey-City, N. J., a corporation of Delaware Application November 30, 11939, SerialNo. 30627.85

(Cl. ISS- 49) 3 Claims.

This invention relates to the production of motor fuels of the gasoline type as well as higher boiling motor fuels adapted for engines using heavy fuels.

It is a particular object of the invention to provide an improved fuel for spark ignition internal combustion engines, such as those of the Hesselman type, using fuel oils heavier than gasoline, but operating under moderate compressions as compared with the high compressions used in engines of the Diesel type which rely on compression for ignition.

In accordance with the invention, a high boiling motor fuel having an extremely high concentration of naphthenic and aromatic hydrocarbons and possessing high anti-knock value, is made while simultaneously making a high antiknock motor fuel of the gasoline type.

The invention contemplates a process in which a charging stock, such as gas oil or kerosene, isi

subjected to cracking to Veffect conversion into lower boiling hydrocarbons, the resulting cracked products separated into vapors and residue and the separated vapors fractionated to separate out a condensate, higher boiling than thev charging stock, comprising products of polymerization and containing a high concentration of cyclic compounds including naphthenic and aromatic hydrocarbons. This polymer condensate is then combined with a low boiling hydrocarbon fraction, such as gasoline, undergoing cracking or reforming and is subjected to partial conversion into lower boiling constituents of increasedfantiknock quality and combination Vwith polymer products produced in the reforming operation. The resulting products produced in the conversion of these combined stocks are then fractionated to recover the desired anti-knock gasoline and a higher boiling fuel product of high antiknock quality.

A feature of the invention is the introduction of the polymer or cyclic condensate into an intermediate point in the light hydrocarbon cracking or reforming zone soas' to provide a shorter time of reaction for the polymer condensatethan is used in the cracking or reforming of the light oil.

The invention furthermore contemplates a combination cracking process for the processing of a crude oil charging stock for the production of both anti-knock gasoline and a higher boiling anti-knock motor fuel in which the crude petroleum'is fractionated to form a crude residue, a low boiling fraction and a higher boiling condensate fraction, in which the residue is subjected to -crackingand the resulting cracked products separatelyfractionated to obtain `a low boiling .fraction and a higher-boiling condensate fraction, in which the low boiling fractions from the crude distillation and from the cracking of the residue are subjected to cracking or reforming, in which'the higher boiling straight-run `condensate and the-higher boiling condensate from the cracking of the residue are passedtoa cracking zone .and subjected tov cracking conditions to -effect `conversion into anti-knock `gasoline con- Vmer condensate is .introduced into the low boiling hydrocarbon cracking or-reforming zone for conversion and reaction therein with the lowboilving constituents undergoing conversion and in which the resulting products of conversion are fractionated `to recover the desired loW boiling and high boiling motor fuels of high anti-knock value.

"For the purpose of more completely disclosing the invention, reference will now be had to the accompanying drawing which is a diagrammatic elevation ofi-an apparatus adapted for practicing alparticular embodiment `of the invention.

'In the apparatus thus illustrated, the crude petroleum charging stock, after being heated to a desireddistilling temperature by heat exchange with cracked products of thev system or by other heating means, isintroduced by a pump Ii) to a stripping and fractionating tower I I, the heated oil is separated into vaporsand residue in the tower and the'vapors are fractionated to form a .naphtha fraction collecting in tray I2 and a higherboilingcondensate collecting in tray I3. Light gasoline constituents, which may not require reforming, pass overhead as vapors to .a condenser I4 and the distillate is collected in a receiving drum or gas separator I5.

Crude residuum is drawn from the tower II through a line I- and directed by a pump I'I to a heating coil I8, positioned in furnace IS adapted for supplying cracking temperature to effect cracking,orViscosity-breaking of the residue and effect conversion into vintermediate constituents -aswellas ,into gasoline constituents. The resultant viscosity-broken Aproducts are separated Yinto -vapors and residue in a separating-and fractionating tower 20 from which the residue may be Withdrawn through .a line 2l. The upper sec:-

tions of the tower 20 are equipped with suitable fractionating elements and cooling means to effect fractionation of the separated vapors. Primary or heavy reflux condensate collecting in a tray 22 may be cycled by a pump 23 through a line 24 to the viscosity-breaking coil |8. Intermediate or gas oil condensate is collected in tray 25 and a naphtha condensate is collected in tray 26. Light gasoline constituents which may not require reforming, pass overhead from the tower 20 to a condenser 21 and the distillate is collected in a distillate receiver or gas separator 28.

The condensate fraction collecting in tray I3 of tower is conducted by -a pump 29 through a line 30 to a heating coil 3| positioned in a furnace 32 adapted for supplying the desired cracking temperature. Intermediate condensate from tray 25 of tower 20 is also charged to heating coil 3| by a pump 33 and line 34. The resultant cracked products pass into a reaction chamber or separator 35 wherein separation of vapors from residue takes place. The residue is withdrawn through a line 38 and the separated vapors pass to a fractionating tower 31 which is provided with conventional fractionating elements and cooling means to accomplish the desired fractionation. The fractionation is so conducted in the tower 31 as to segregate at the bottom of the tower a reflux condensate higher boiling than that of the charge to the cracking coil 3|, while a lower boiling condensate, higher boiling than gasoline, is collected in a tray 38. The latter condensate may be cycled by a pump 39 and line 40 to the cracking coil 3|. Gasoline or naphtha constituents pass overhead from the tower as vapors to a condenser 4| and the distillate is collected in a receiving drum or gas separator 42.

The naphtha fraction collecting in the tray |2 of the crude stripping tower is conducted by a pump 43 through a line 44 to a heating coil 45 positioned in furnace 46 and adapted for heating the naphtha to a cracking temperature adequate to effect reforming into constituents of increased anti-knock quality. Viscosity-breaker naphtha collecting in tray 26 of tower 20 may be charged by pump 41 and line 48 to the reforming coil 45. The heavy cyclic condensate collecting in the bottom of tower 31 is conducted by pump 49 through line 50 by which it is introduced into an intermediate point of the coil 45. The resultant products of reaction pass from the coil 45 into a reaction chamber or separator in which the vapors may be separated from any residual products of reaction, the tar or residue being withdrawn through a line 52. The separated vapors pass to a fractionating tower 53 which is provided with conventional fractionating elements and cooling means to effect the desired fractionation. Vapors of desired distillation range for gasoline pass overhead from the tower to a condenser 54 and the distillate is collected in a receiving drum or gas separator 55. Higher boiling cyclic condensate may be withdrawn through a line 55. A plurality of trapout trays, as 51 and 58, may be provided for the collection of particular fractions of cyclic or polymer condensate.

The fraction collecting in receiver 55 constitutes a desired gasoline type of motor fuel which may be blended with the cracked gasoline co1- lecting in receiver 42 and may be subjected to such rectification as may be desired. The fraction withdrawn through line 5B or withdrawn from any of the trays 51 and 58, contains a high concentration of cyclic compounds, being rich in aromatics and naphthenes, and constitutes the desired higher boiling motor fuel product of high anti-knock value. This product may be blended with other high anti-knock distillate of suitable boiling range, such as heavy polymers produced in gas polymerization or the products of gas pyrolysis or gas reversion for the preparation of a high grade fuel for internal combustion engines using heavy motor fuels.

In practicing the invention the crude oil may be distilled to produce a residue of about 650 F. to 750 F. initial boiling point, a gas oil cut having a boiling range of 500 F. or 550 F. up to about 750 F. and a heavy naphtha cut having a boiling range of 250 F. up to about 500 F. or 550 F. The residue is subjected to viscosity-breaking under suitable conditions of temperature and pressure to effect conversion into a high yield of intermediate constituents as well as into gasoline constituents. The vapors from the viscositybreaking operation are fractionated in tower 20 to separate a reliux condensate at 22 having a higher boiling range than that of the material which it is desired to subject to cracking in the gas oil cracking coil 3| and this high boiling condensate is cycled to the viscosity-breaking coil I8. In lieu of cycling this condensate to the coil I8, it may advantageously be passed to a separate cracking zone and the cracked products returned to the tower 2U. The intermediate 4condensate collecting in tray 25 may comprise constituents of similar boiling range to that of lthe straight-run gas oil and the mixture of straightrun and viscosity-breaker gas oil, together with the cycle condensate withdrawn from tray 38 which may have a boiling range of about 400 F. to 700 F. or 750 F. is subjected to cracking under suitable conditions of temperature and pressure but preferably under conditions of relatively high cracking per pass so as to effect conversion into high anti-knock gasoline. The heavy cyclic or polymer condensate collected at the base of tower 31 may have an initial boiling point of the order of '100 F. or '150 F., the exact temperature depending upon the endpoint of the oil charged to the cracking coil 3|. In any case, the polymer condensate will consist largely of constituents boiling in the range of '150 F. to 850 F. (determined by vacuum distillation and interpolated to an atmospheric pressure basis). The viscosity-breaker naphtha fraction withdrawn from tray 25 and admixed with straightrun naphtha withdrawn from tray |2 of tower may have a boiling range similar to that'of the straight-run ynaphtha and the mixture is subjected to conditions of temperature and pressure in the coil 45 adapted for accomplishing the desired reformation into constituents of increased anti-knock quality. This temperaturewillbe in excess of 850 F. and is preferably of the order of 900 F. or 1000 F. The pressure employed in the reforming of the naphtha and in the conversion of the heavy polymer condensate which undergoes reaction with the naphtha, is preferably relatively high, such as of the order of 600 to 1000 pounds.

In a specinc example of the invention, crude residue having an initial boiling point of '100J F. is subjected to viscosity-breaking in coil I8 at a temperature Vof 900 F. under 4.00V pounds pressure, a4 fraction having an initial boiling point of '100 F. being withdrawn from tray 22 and cycled to the heating coil I8. 'An intermediate Afraction having a boilingrange of 500 F. to '700 F. is withdrawn fromV tray 25 of towerV 28 and combined with a similar 'boilingrange cut/ of gas 'oil `taken Lfrom Vtray f3 of lthe crude stripping tower Vand lthe Vmixture `is subjected Jto vcracking in coil 3 I data. temperature of 950 F. under i 400 `pounds-pressure. I'h'e vapors lfiomthecracking i operation 'are -fraction'atedin tower A'3"l`fto form a condensate atthebottom f the towerhaving an initial boilir'igpoint` of about '700 landconsisting substantially entirely of 'components boiling 'above those 'of Ythe'oil char'g'ed to the'cracking tion withdrawn from tray 26 of the tower 20 for` passage to the reforming coil 45. The naphtha is raised to a temperature of 950 F. in the first portion of the heating coil 45 and subjected to reforming, and the heavy cyclic product withdrawn from tower 31 is combined with the naphtha undergoing reforming. 'Ihe mixture undergoes reaction in the subsequent portions of the heating coil at a temperature of about 850 F.-900 F. while under pressure of about 800 pounds. A gasoline product of 400 F. endpoint is separated from the higher boiling reflux condensate and collected as a distillate in receiver 52 while higher boiling condensate of desired boiling range and viscosity and consisting predominantly of polymer products of reaction is withdrawn from the tower to constitute the high boiling motor fuel rich in aromatic and naphthenic compounds.

It is advantageous to charge to the reforming coil 45 a naphtha fraction having approximately the same endpoint as that desired for the gasoline distillate collected in receiver 55 in which case the high boiling motor fuel product withdrawn from the tower 53 will consist entirely of polymer products of reaction.

In one method of practicing the invention, the crude residuum as withdrawn from tower Il, instead of being subjected to a viscosity-breaking operation, is subjected to coking for immediate conversion into a maximum yield of overhead products and the vapors from the coking operation are fractionated to separate out a gas oil stock of desired boiling range which is combined with the straight-run gas oil and the mixture subjected to cracking, while straight-run naphtha as well as naphtha from the coking operation, if desired, is subjected to a separate reforming operation and a polymer condensate, consisting essentially of constituents higher boiling than the gas oil charged to the gas oil cracking zone, is separated out from the resultant products of the gas oil cracking. and directed to the reforming zone, particularly to an intermediate point therein, for partial conversion into lower boiling constituents within the gasoline boiling range and for combination with naphtha constituents undergoing reforming to form high boiling antiknock motor fuel as well as anti-knock motor fuel of the gasoline type.

Although a preferred embodiment of the invention has been described herein, it will be understood that various changes and modifications may be made therein, while securing to a greater or less extent some or all of the benefits of the invention, Without departing from the spirit and scope thereof.

I claim:

.1. In the manufacture of motor fuel, the processthat comprises subjecting a naphtha stock in a reforming Zone to cracking temperature adequat'e to Veffect reformation into gasoline constituents of increased anti-'knock quality, subjecting a higher boiling vcharging stock of given boiling range ina separate cracking zone to cracking conditions of temperature and pressure-to Veffect conversion` into lower boiling hydrocarbons and 'higher boiling polymer products, separating the vresultant cracked products into vapors and residue, fractionating the separated vapors to separate from lower boiling products a completely synthetic polymer product consisting essentially of constituents higher boilin-g than said,y higher boiling stock, directing said polymer product to said reforming zone for conversion and combination with reaction products of the reforming and subjecting the commngled constituents to conversion in the absence of any added constituents higher boiling than said naphtha stock, separating the resultant products of conversion from the reforming zone into vapors and residue, and fractionating the separated vapors to separate a gasoline product from a higher boiling completely synthetic condensate comprising polymer products of reaction and withdrawing the condensate as another product of the process.

`2. In the manufacture of motor fuel, the process that comprises subjecting a naphtha stock in a reforming zone to cracking temperature adequate to effect reformation into gasoline constituents of increased anti-knock quality, subjecting a higher boiling charging stock of given boiling range in a separate cracking zone to cracking conditions of temperature and pressure to effect conversion into lower boiling hydrocarbons and higher boiling polymer products, separating the resultant cracked products into vapors and residue, subjecting the separated vapors to fractionation to form a gasoline distillate, an intermediate condensate higher boiling than gasoline and a completely synthetic condensate consisting essentially of polymer products of reaction higher boiling than said higher boiling charging stock, directing said synthetic condensate to said reforming Zone for conversion and -combination with reaction products of the reforming land subjecting the commngled constituents to conversion in the absence of any added constituents higher boiling than said naphtha stock, separating the resultant products of conversion from the reforming zone into vapors and residue, and fractionating the separated vapors to separate a gasoline product from a higher boiling completely synthetic condensate comprising polymer products of reaction and withdrawing the condensate as another product of the process.

3. In the manufacture of motor fuel, the process that 4comprises fractionating crude petroleum to produce a residue, a gas oil fraction and a naphtha fraction, subjecting said residue to cracking conditions of temperature and pressure to effect conversion into lower boiling products,

separately fractionating the resultant cracked products to obtain a gas oil fraction and a naphtha fraction, combining said naphtha fractions and subjecting the mixture in a reforming Zone to cracking temperature adequate to effect reformation into gasoline constituents of in-V creased anti-knock quality, combining said gas oil fractions and subjecting the mixture ina separate cracking zone to cracking conditions of reforming and subjecting the commingled constituents to conversion in the absence of any added constituents higher boiling than said naphtha stock, separating the resultant products of conversion from the reforming zone into vapors and residue, and fractionating the separated vapors to separate a gasoline product from higher boiling completely synthetic condensate comprising polymer products of reaction and withdrawing 10 the condensate as another product of the process.

HAROLD V. ATWELL. 

